Add hostname resolution support to IP lookup endpoint

- Accept hostnames in addition to IP addresses for /ip endpoints
- Resolve A and AAAA records for hostnames
- Return list of results with info for each resolved IP
- Include hostname in response when resolving hostnames
- Report per-IP errors while still returning successful lookups

internal/server/handlers.go

@@ -367,27 +367,49 @@ func (s *Server) handleIPLookup() http.HandlerFunc {
 	return s.handleIPInfo()
 }
 
+// HostLookupResponse is returned when looking up a hostname.
+type HostLookupResponse struct {
+	Hostname string              `json:"hostname,omitempty"`
+	Results  []*database.IPInfo  `json:"results"`
+	Errors   []string            `json:"errors,omitempty"`
+}
+
 // handleIPInfo returns a handler that provides comprehensive IP information.
 // Used for /ip, /ip/{addr}, and /api/v1/ip/{ip} endpoints.
+// Accepts both IP addresses and hostnames. For hostnames, resolves A and AAAA records.
 func (s *Server) handleIPInfo() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		// Get IP from URL param, falling back to client IP
-		ip := chi.URLParam(r, "ip")
-		if ip == "" {
-			ip = chi.URLParam(r, "addr")
+		// Get IP/hostname from URL param, falling back to client IP
+		target := chi.URLParam(r, "ip")
+		if target == "" {
+			target = chi.URLParam(r, "addr")
 		}
-		if ip == "" {
+		if target == "" {
 			// Use client IP (RealIP middleware has already processed this)
-			ip = extractClientIP(r)
+			target = extractClientIP(r)
 		}
 
-		if ip == "" {
+		if target == "" {
 			writeJSONError(w, http.StatusBadRequest, "Could not determine IP address")
 
 			return
 		}
 
-		// Look up comprehensive IP information
+		// Check if target is already an IP address
+		if parsedIP := net.ParseIP(target); parsedIP != nil {
+			// Direct IP lookup
+			s.lookupSingleIP(w, r, target)
+
+			return
+		}
+
+		// Target is a hostname - resolve and look up each IP
+		s.lookupHostname(w, r, target)
+	}
+}
+
+// lookupSingleIP handles lookup for a single IP address.
+func (s *Server) lookupSingleIP(w http.ResponseWriter, r *http.Request, ip string) {
 	ipInfo, err := s.db.GetIPInfoContext(r.Context(), ip)
 	if err != nil {
 		if errors.Is(err, database.ErrInvalidIP) {
@@ -408,6 +430,66 @@ func (s *Server) handleIPInfo() http.HandlerFunc {
 	if err := writeJSONSuccess(w, ipInfo); err != nil {
 		s.logger.Error("Failed to encode IP info", "error", err)
 	}
+}
+
+// lookupHostname resolves a hostname and looks up info for each IP.
+func (s *Server) lookupHostname(w http.ResponseWriter, r *http.Request, hostname string) {
+	ctx := r.Context()
+
+	// Resolve hostname to IP addresses
+	ips, err := net.DefaultResolver.LookupHost(ctx, hostname)
+	if err != nil {
+		writeJSONError(w, http.StatusBadRequest, "Failed to resolve hostname: "+err.Error())
+
+		return
+	}
+
+	if len(ips) == 0 {
+		writeJSONError(w, http.StatusNotFound, "No IP addresses found for hostname")
+
+		return
+	}
+
+	response := HostLookupResponse{
+		Hostname: hostname,
+		Results:  make([]*database.IPInfo, 0, len(ips)),
+	}
+
+	// Track ASNs that need WHOIS refresh
+	refreshASNs := make(map[int]bool)
+
+	// Look up each resolved IP
+	for _, ip := range ips {
+		ipInfo, err := s.db.GetIPInfoContext(ctx, ip)
+		if err != nil {
+			response.Errors = append(response.Errors, ip+": "+err.Error())
+
+			continue
+		}
+
+		response.Results = append(response.Results, ipInfo)
+
+		if ipInfo.NeedsWHOISRefresh {
+			refreshASNs[ipInfo.ASN] = true
+		}
+	}
+
+	// Queue WHOIS refresh for stale ASNs (non-blocking)
+	if s.asnFetcher != nil {
+		for asn := range refreshASNs {
+			s.asnFetcher.QueueImmediate(asn)
+		}
+	}
+
+	// Return response
+	if len(response.Results) == 0 {
+		writeJSONError(w, http.StatusNotFound, "No routes found for any resolved IP")
+
+		return
+	}
+
+	if err := writeJSONSuccess(w, response); err != nil {
+		s.logger.Error("Failed to encode hostname lookup response", "error", err)
 	}
 }